Hi, I am having trouble understanding aggregate functions.

In Filemaker The Missing Manual it states: "If you rever an aggregate function to even one related fiel, Filemaker aggregates that field's values from EVERY related record."

But say I use Count(LearnerID) in a calculation, it only counts the current active record. Not ALL records. How do I do that?

Count(LearnerID) does NOT refer to a RELATED field. Count (RelatedTable::SomeField) does.

Stupid me Ok it works now. How can I tell it to count only certian fields, with a certian value? For Instance Count all Active Status fields?

There's no COUNTIF() function in Filemaker, so any conditions you have, you need to set them up in the related table - either as a calculation field with a numeric result, or as a numeric field to begin with (see here).

Alternatively, you could include ActiveStatus in the definition of the relationship - so that only active records are considered related. With a global gShowStatus field on the parent side, you can switch the relationship to include active-only/non-active/both as needed.